Pulsed dynamics and itinerant cat state generation in a Kerr parametric oscillator

Kerr parametric oscillators (KPOs) have been proposed as a platform for alternative implementations of quantum computing [1] and for quantum simulations [2]. These goals can only be reached using a scalable KPO architecture with high internal quality factors and low pure dephasing. An experiment that can be performed using a single low-loss KPO is the generation of itinerant cat states [3].

Here we present a planar KPO design consisting of a large island shunted to the ground by a single SQUID, with an internal quality factor exceeding 10⁵. We investigate the dynamics of the KPO under pulsed excitations at the fundamental and around double the fundamental frequency, both by monitoring the averaged field emitted by the KPO and by performing Wigner tomography. Using a carefully shaped parametric pulse, we generate itinerant cat states.